Chapter 9 — Biotechnology: Principles and Processes

Class 12 Biology Chapter 9 covers the principles and processes of biotechnology, focusing on recombinant DNA technology — how restriction enzymes, cloning vectors, and bioreactors are used to produce useful proteins and genetically modified organisms.

Biotechnology: Principles and Processes (Class 12 Biology Chapter 9) explains how modern biotechnology uses genetic engineering and bioprocess engineering to produce useful products. The chapter covers restriction enzymes (molecular scissors that cut DNA at specific palindromic sequences), cloning vectors such as plasmids and bacteriophages, PCR for DNA amplification, gel electrophoresis for DNA separation, and bioreactors for large-scale protein production. Stanley Cohen and Herbert Boyer pioneered recombinant DNA technology in 1972, forming the foundation of modern biotechnology.

1. 01Restriction endonucleases cut DNA at specific palindromic recognition sequences, producing sticky ends that facilitate joining of DNA fragments using DNA ligase
2. 02Stanley Cohen and Herbert Boyer constructed the first recombinant DNA in 1972 by linking an antibiotic resistance gene with a Salmonella typhimurium plasmid
3. 03Cloning vectors must have an origin of replication (ori), a selectable marker, and suitable cloning sites to allow foreign DNA to replicate in host cells
4. 04PCR (Polymerase Chain Reaction) uses thermostable DNA polymerase from Thermus aquaticus to amplify a target DNA segment up to approximately one billion copies
5. 05DNA can be introduced into host cells by chemical treatment with calcium ions (heat shock method), micro-injection, biolistics (gene gun), or disarmed pathogen vectors
6. 06Bioreactors (100–1000 litre capacity) provide optimal temperature, pH, oxygen, and nutrient conditions for large-scale production of recombinant proteins